Semiconductor device

ABSTRACT

A semiconductor device includes two or more semiconductor elements, a lead with island portions on which the semiconductor elements are mounted, a heat dissipation member for dissipating heat from the island portions, a bonding layer bonding the island portions and the heat dissipation member, and a sealing resin covering the semiconductor elements, the island portions and a part of the heat dissipation member. The bonding layer includes mutually spaced individual regions provided for the island portions, respectively.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device.

2. Description of the Related Art

Various semiconductor devices are conventionally known. One of the knownsemiconductor devices is an IPM (Intelligent Power Module). Asemiconductor device of this type includes a plurality of semiconductorelements, a lead including a plurality of island portions, a heatdissipation member and a sealing resin. The semiconductor elements aremounted on the island portions, respectively. The island portions arebonded to the heat dissipation member. The sealing resin covers thesemiconductor elements, the island portions and the heat dissipationmember. The semiconductor elements are electrically connected to eachother appropriately via wires, so are the semiconductor elements and thelead. An example of the IPM is disclosed in JP-A-2011-243839.

In a semiconductor device configured as an IPM, the semiconductorelement heats up during use. Due to the heat, the lead, the heatdissipation member and the sealing resin are thermally expanded.Generally, the lead, the heat dissipation member and the sealing resinare made of different materials. Thus, thermal stress is generated atthe portions where these members are bonded to each other. When e.g. thelead and the sealing resin partially separate from each other due tothermal stress, proper insulation may not be provided between thesemiconductor elements or between the semiconductor elements and thelead.

Since the heat dissipation member is provided for dissipating the heatgenerated at the semiconductor element to the outside, part of the heatdissipation member is exposed from the sealing resin. Thus, the edge ofthe interface between the heat dissipation member and the sealing resinis exposed to the outside. Depending on use environment of thesemiconductor device, moisture and so on may enter the interface. Whenmoisture enters deep into the device, the heat dissipation member andthe sealing resin may separate from each other, which may lead tocorrosion of e.g. the semiconductor element.

In a semiconductor device configured as IPM, thermal stress is appliedalso on the wires bonded to the semiconductor elements or the lead.Since each wire has a relatively discontinuous shape at the bondingportion, stress tends to be intensively applied on the bonding portion.Due to such intensive stress application, the wire may be detached fromthe semiconductor element or the lead.

Thermal stress is applied also on the portion where the semiconductorelement and the island portion are bonded to each other. Thesemiconductor element is bonded to the island portion with a bondingmaterial such as solder or Ag paste. When the bonding strength of thesemiconductor element and the island portion with the bonding materialis insufficient, the semiconductor element may be detached from theisland portion.

Generally, the lead is made of a metal. Thus, the portion where the leadand the sealing resin are bonded together is the portion where differentmaterials, i.e., metal and resin are bonded together. Since thecoefficient of thermal expansion is considerably different between metaland resin, thermal stress is likely to occur. When the lead and thesealing resin become detached from each other due to thermal stress,proper insulation cannot be provided.

SUMMARY OF THE INVENTION

The present invention has been conceived under the circumstancesdescribed above. It is therefore an object of the present invention toprovide a semiconductor device capable of preventing detachment of thesealing resin. Another object of the present invention is to provide asemiconductor device capable of preventing detachment of wires. Anotherobject of the present invention is to provide a semiconductor devicecapable of preventing detachment of the semiconductor elements and theisland portions. Another object of the present invention is to provide asemiconductor device capable of preventing detachment of the lead andthe sealing resin.

According to an embodiment of the present invention, there is provided asemiconductor device including: semiconductor elements; a lead includingisland portions on which the semiconductor elements are mounted; a heatdissipation member for dissipating heat from the island portions; abonding layer bonding the heat dissipation member to the islandportions; and a sealing resin covering the semiconductor elements, theisland portions and a part of the heat dissipation member. The bondinglayer includes individual regions provided for the island portions,respectively. The individual regions are spaced apart from each other.

Preferably, each of the individual regions has an outer edge positionedinward of an outer edge of a corresponding one of the island portions.

Preferably, the heat dissipation member is made of a ceramic material.

Preferably, the heat dissipation member includes an exposed surface thatis exposed from the sealing resin and flush with an surface of thesealing resin.

Preferably, the heat dissipation member is in a form of a plate.

Preferably, the semiconductor elements include at lease one powersemiconductor element.

Preferably, at least two of the semiconductor elements are mounted onone of the island portions.

Preferably, the island portions are aligned in a direction.

Preferably, the semiconductor device of an embodiment of the presentinvention further includes terminal portions connected to the islandportions, respectively, where the terminal portions are exposed from thesealing resin.

Preferably, each of the island portions is formed with recesses, whichmay be arranged in a predetermined pattern. In an embodiment, each ofthe recesses is circular in cross section. In each of the islandportions, the recesses may be arranged to surround the semiconductorelement mounted on the island portion.

Preferably, each of the island portions has a smooth surface formounting a semiconductor element.

Preferably, the semiconductor device of an embodiment of the presentinvention further includes a bonding material for bonding the islandportions to the bottom surfaces of the respective semiconductorelements. Preferably, the bottom surfaces of the respectivesemiconductor elements have a higher wettability to the bonding materialin a molten state than the island portions.

Preferably, each of the semiconductor elements includes a bottom-surfaceelectrode that provides the bottom surface of each semiconductorelement.

Preferably, each of the semiconductor elements includes a semiconductormain body, and the bottom-surface electrode entirely covers the bottomsurface of the semiconductor main body.

Preferably, each of the island portions includes a trench disposed on anouter side of the semiconductor element mounted.

Preferably, in each of the island portions, the bonding material isdisposed inward of the trench.

Preferably, in each of the island portions, the trench surrounds thesemiconductor element mounted.

Preferably, in each of the island portions, the recesses are provided onan outer side of the trench.

Other features and advantages of the present invention will become moreapparent from detailed description given below with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a semiconductor deviceaccording to a first embodiment of the present invention;

FIG. 2 is a plan view of the semiconductor device of FIG. 1;

FIG. 3 is a plan view of the semiconductor device of FIG. 1;

FIG. 4 is a front view of the semiconductor device of FIG. 1;

FIG. 5 is a side view of the semiconductor device of FIG. 1;

FIG. 6 is a schematic sectional view taken along lines VI-VI in FIG. 3;

FIG. 7 is a schematic sectional view taken along lines VII-VII in FIG.3;

FIG. 8 is a schematic plan view of island portions of the semiconductordevice of FIG. 1;

FIG. 9 is a schematic sectional view taken along lines IX-IX in FIG. 8;

FIG. 10 is a schematic sectional view taken along lines X-X in FIG. 8;

FIG. 11 is a schematic sectional view taken along lines IX-IX in FIG. 8;

FIG. 12 is a schematic sectional view illustrating a plate material forforming a heat dissipation member;

FIG. 13 is a schematic sectional view illustrating the step of dividingthe plate material shown in FIG. 12;

FIG. 14 is a schematic sectional view illustrating another example ofthe heat dissipation member;

FIG. 15 is a schematic sectional view illustrating another example ofthe plate material for forming the heat dissipation member;

FIG. 16 is a schematic plan view illustrating an island portion of thesemiconductor device shown in FIG. 1;

FIG. 17 is a schematic enlarged sectional view taken along linesXVII-XVII in FIG. 16;

FIG. 18 is a schematic enlarged sectional view taken along linesXVIII-XVIII in FIG. 16;

FIG. 19 is a schematic plan view illustrating island portions, a bondinglayer and a heat dissipation member of the semiconductor device of FIG.1;

FIG. 20 is a photograph of a wire of the semiconductor device of FIG. 1;

FIG. 21 is a schematic sectional view illustrating a process of making awire of the semiconductor device of FIG. 1;

FIG. 22 is a schematic sectional view illustrating a process of making awire of the semiconductor device of FIG. 1;

FIG. 23 is a schematic sectional view illustrating a process of making awire of the semiconductor device of FIG. 1;

FIG. 24 is a schematic sectional view illustrating a process of making awire of the semiconductor device of FIG. 1;

FIG. 25 is a schematic sectional view illustrating a process of making awire of the semiconductor device of FIG. 1;

FIG. 26 is a schematic sectional view illustrating a process of making awire of the semiconductor device of FIG. 1;

FIG. 27 is a schematic sectional view illustrating a process of making awire of the semiconductor device of FIG. 1;

FIG. 28 is a schematic sectional view illustrating a process of making awire of the semiconductor device of FIG. 1;

FIG. 29 is a schematic sectional view illustrating a process of making awire of the semiconductor device of FIG. 1; and

FIG. 30 is a plan view illustrating a semiconductor device according toa second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention are described below withreference to the accompanying drawings.

FIGS. 1-7 illustrate a semiconductor device according to a firstembodiment of the present invention. The semiconductor device A1 of thisembodiment includes a lead 100, a heat dissipation member 200, a bondinglayer 300, a plurality of semiconductor elements 410, 420, 430, 440, aplurality of passive components 490, bonding materials 510, 520, wires600, 650 and a sealing resin 700. For instance, the semiconductor deviceA1 is structured as an IPM for drive control of e.g. an inverter motor.For instance, the semiconductor device A1 is about 38 mm in thedimension in the direction x, about 24 mm in the dimension in thedirection y and about 3.5 mm in the dimension in the direction z(thickness of the sealing resin 700).

FIG. 1 is a perspective view of the semiconductor device A1. For easierunderstanding, with respect to the sealing resin 700, only the mainouter line is indicated by double-dashed lines. FIG. 2 is a plan view ofthe semiconductor device A1. FIG. 3 is a plan view of the semiconductordevice A1, in which the sealing resin 700 is indicated by double-dashedlines for easier understanding. FIG. 4 is a front view of thesemiconductor device A1. FIG. 5 is a side view of the semiconductordevice A1. FIG. 6 is a sectional view in the z-x plane taken along linesVI-VI in FIG. 3, in which terminal portions are omitted for easierunderstanding. FIG. 7 is a sectional view in the y-z plane taken alonglines VII-VII in FIG. 3. In the sectional views referred to below,illustration of wires 600 and wires 650 is omitted for easierunderstanding.

The lead 100 is an electrically conductive supporting means thatsupports the semiconductor elements 410, 420, 430, 440 and provides anelectrical conduction path to the semiconductor elements. In thisembodiment, the lead 100 includes island portions 110, 120, 130, 140,150, pad portions 160, 170, 180 and terminal portions 111, 121, 141,151, 161, 171, 181, 191. The lead 100 is made of a metal and in thisembodiment made of Cu. The thickness of the lead 100 is e.g. about 0.42mm. The lead 100 may be formed by punching, cutting or bending a metalplate.

The island portions 110, 120, 130, 140, 150 are the portions on whichthe semiconductor elements 410, 420, 430, 440 and the passive components490 are mounted. In this embodiment, the single island portion 110 andthe island portions 120 (three portions in the illustrated example) arealigned in the direction x. The island portion 130 and the islandportion 140 are aligned in the direction x. The island portions 110, 120and the island portions 130, 140 are aligned in the direction y. Theisland portions 150 (three portions in the illustrated example) areadjacent to the island portion 130 in the direction y.

FIG. 8 is a schematic plan view illustrating the island portion 110 andthe related portions. FIG. 9 is a schematic sectional view in the z-xplane taken along lines IX-IX in FIG. 8. FIG. 10 is a schematicsectional view in the z-x plane taken along lines X-X in FIG. 8. Theisland portion 110 is generally rectangular. The semiconductor elements410 and 420 are mounted on the island portion 110. Specifically, in thisembodiment, three semiconductor elements 410 and three semiconductorelements 420 are mounted on the island portions 110. The threesemiconductor elements 410 are aligned in the direction x, so are thethree semiconductor elements 420. The semiconductor elements 410 arespaced apart from the semiconductor elements 420, respectively, in thedirection y such that each semiconductor element 410 overlaps solely acorresponding one of the semiconductor elements 420 as viewed in thedirection y.

The island portion 110 is formed with a plurality of recesses 112 and aplurality of trenches 113. The recesses 112 open in the surface of theisland portion 110 on which the semiconductor elements 410 and 420 aremounted. In this embodiment, the recesses 112 are circular in crosssection. However, the shape of the recesses 112 in the present inventionis not limited to this. The recesses 112 are provided on the islandportion 110 at portions avoiding the trenches 113 or avoiding theregions surrounded by the trenches 113. In this embodiment, the recesses112 are arranged in a matrix along the direction x and the direction y.

The trenches 113 are formed so as to surround the semiconductor elements410 or the semiconductor elements 420. The trenches 113 open in thesurface of the island portion 110 on which the semiconductor elements410 and 420 are mounted. The trench 113 on the upper side in FIG. 8includes a rectangular frame portion and two strip portions elongated inthe direction y and dividing the frame portion into three parts. Thus,the trench 113 on the upper side in FIG. 8 surrounds three regions inwhich the semiconductor elements 410 are arranged, respectively. Each ofthe three trenches 113 on the lower side in FIG. 8 is in the form of arectangular frame. Each of these trenches 113 surrounds a region onwhich one of the semiconductor elements 420 is mounted. Although it ispreferable that each trench has a closed shape that surrounds thesemiconductor element entirely, the present invention is not limited tothis. For instance, the trench may be made up of a plurality of separateportions arranged around the semiconductor element.

FIG. 16 is a schematic plan view illustrating the island portion 120located at the left end in FIG. 3 and the related portions. Thestructures of other island portions 120 shown in FIG. 3 are basicallythe same as the structure of this island portion 120 except somedifferences in shape. FIG. 17 is a schematic sectional view in the y-zplane taken along lines XVII-XVII in FIG. 16. The island portion 120 isgenerally in the form of a rectangle elongated in the direction y. Thesemiconductor elements 410 and 420 are mounted on the island portion120. Specifically, in this embodiment, one of the semiconductor elements410 and one of the semiconductor elements 420 are mounted on the islandportion 120. The semiconductor element 410 and the semiconductor element420 are aligned in the direction y.

The island portion 120 is formed with a plurality of recesses 122 and aplurality of trenches 123. The recesses 122 open in the surface of theisland portion 120 on which the semiconductor elements 410 and 420 aremounted. In this embodiment, the recesses 112 are circular in crosssection. However, the shape of the recesses 112 in the present inventionis not limited to this. The recesses 122 are provided on the islandportion 110 at portions avoiding the trenches 123 or avoiding theregions surrounded by the trenches 123. In this embodiment, the recesses122 are arranged in a matrix along the direction x and the direction y.

The trenches 123 are formed so as to surround the semiconductor element410 or the semiconductor element 420. The trendies 123 open in thesurface of the island portion 120 on which the semiconductor elements410 and 420 are mounted. The upper trench 123 in FIG. 16 is in the formof a rectangular frame. In the region surrounded by this trench 123 isarranged the semiconductor element 410. The lower trench 123 in FIG. 16is also in the form of a rectangular frame. In the region surrounded bythis trench 123 is arranged the semiconductor element 420. Although itis preferable that each trench has a closed shape that surrounds thesemiconductor element entirely, the present invention is not limited tothis. For instance, the trench may be made up of a plurality of separateportions arranged around the semiconductor element.

The island portion 120 shown in FIG. 16 is formed with two corners 125and an arcuate portion 126. The two corners 125 are provided on theupper end in FIG. 16 (on the side farther from the terminal portion 121,which is described later), whereas the arcuate portion 126 is providedon the lower end in FIG. 16 (on the side closer to the terminal portion121). In FIG. 16, the corners 125 are on the upper side of thesemiconductor elements 410, 420 (on the side farther from terminalportion 121), whereas the arcuate portion 126 is on the lower side ofthe semiconductor elements 410, 420 (on the side closer to the terminalportion 121). In this embodiment, at each of the corners 125, two sidesof the island portion 120 are connected to each other to form an angleof 90°. At the arcuate portion 126, two sides of the island portion 120are connected to each other to form an arc.

As shown in FIGS. 1-3 and FIG. 7, the island portion 130 is adjacent tothe island portion 110 in the direction y. The island portion 130 isgenerally in the form of a rectangle elongated in the direction x. Thesemiconductor element 430 is mounted on the island portion 130. Thesemiconductor element 430 is in the form of a rectangle elongated in thedirection x, similarly to the island portion 130.

The island portion 130 is formed with a plurality of recesses 132. Therecesses 132 open in the surface of the island portion 130 on which thesemiconductor element 4′30 is mounted. In this embodiment, the recesses132 are circular in cross section. However, the shape of the recesses132 in the present invention is not limited to this. The recesses 132are provided on the island portion 130 mainly at portions avoiding thesemiconductor element 430. The recesses 132 may be provided in theregion overlapping the semiconductor element 430 as long as detachmentof the semiconductor element 430 is not caused. In this embodiment, therecesses 132 are arranged in a matrix along the direction x and thedirection y.

The island portion 140 is adjacent to the island portions 120 in thedirection y. The island portion 140 is generally in the form of arectangle elongated in the direction x. The semiconductor element 440 ismounted on the island portion 120. The semiconductor element 440 is alsoin the form of a rectangle elongated in the direction x.

The island portion 140 is formed with a plurality of recesses 142. Therecesses 142 open in the surface of the island portion 140 on which thesemiconductor element 440 is mounted. In this embodiment, the recesses142 are circular in cross section. However, the shape of the recesses142 in the present invention is not limited to this. The recesses 142are provided on the island portion 140 mainly at portions avoiding thesemiconductor element 440. The recesses 142 may be provided in theregion overlapping the semiconductor element 440 as long as detachmentof the semiconductor element 440 is not caused. In this embodiment, therecesses 142 are arranged in a matrix along the direction x and thedirection y. The recesses 142 are formed also in the generallytriangular portion connected to the island portion 140.

The three island portions 150 are adjacent to the island portion 130 inthe direction y. The three island portions 150 are aligned in thedirection x. Each of the island portions 150 is configured to be smallerthan the island portions 110, 120, 130, 140. On each island portion 150is mounted a passive component 490. Each island portion 150 is formedwith a plurality of recesses 152. The recesses 152 open in the surfaceof the island portion 150 on which the passive component 490 is mounted.The recesses 152 are provided at portions avoiding the passive component490. In this embodiment, the recesses 152 are arranged in a matrix alongthe direction x and the direction y. Each island portion 150 is formedwith an arcuate cutout corresponding to a groove 710 of the sealingresin 700, which is described later.

The pad portions 160, 170, 180 are electrically connected to thesemiconductor elements 410, 420, 430, 440 via wires 600, 650.

The pad portions 160 are provided on the lower left of the islandportions 120 in FIG. 3. Each of the pad portions 160 is rectangular. Awire 650 is bonded to each pad portion 160.

The pad portions 170 are arranged adjacent to the island portions 130,140. Each pad portion 170 is generally in the form of a thin elongatedrectangle and comprises an end of a thin strip portion. A wire 600 isbonded to each pad portion 170.

The pad portion 180 is on the left end in FIG. 3. A wire 600 is bondedto the pad portion 180. The pad portion 180 is generally triangular andformed with a plurality of recesses 182. The recesses 182 open in thesurface of the island portion 180 on which the wire 600 is bonded. Therecesses 182 are provided at portions avoiding the wire 600. In thisembodiment, the recesses 182 are arranged in a matrix along thedirection x and the direction y.

For instance, the above-described recesses 112, 122, 132, 142, 152, 182and the trenches 113, 123 may be formed by e.g. etching in the processof making the lead 100. Alternatively, the recesses and trenches may beformed by using a die having a plurality of projections for the cuttingwork or bending work for making the lead 100.

As understood from FIGS. 1, 3 and 7, the lead 100 includes bent portions114 and 124. The bent portion 114 is connected to the island portion 110and bent in such a manner that the side farther away from the islandportions 110 is at a higher position in the direction z. The bentportions 124 are connected to the island portions 120. Each bent portion124 is bent in such a manner that the side farther away from the islandportion 120 is at a higher position in the direction z.

In this embodiment, the portions of the bent portions 114, 124 which arehigher in the direction z are substantially at the same height in thedirection z as the island portions 130, 140, 150 and the pad portions160, 170, 180. In other words, the island portions 110 and 120 arepositioned lower in the direction z than the island portions 130, 140,150 and the pad portions 160, 170, 180.

The terminal portions 111, 121, 141, 151, 161, 171, 181, 191 projectfrom the sealing resin 700. Each of the terminal portions 111, 121, 141,151, 161, 171, 181, 191 is bent at an angle close to 90° and has an endfacing upward in the direction z. The terminal portions 111, 121, 141,151, 161, 171, 181, 191 are used for mounting the semiconductor deviceA1 on e.g. a circuit board.

The terminal portion 111 is connected to the bent portion 114 andelectrically connected to the island portion 110. The three terminalportions 121 are connected to the bent portions 124 and electricallyconnected to the island portions 120. Two terminal portions 141 areconnected to the island portion 140. Three terminal portions 151 areconnected to the three island portions 150, respectively. Three terminalportions 161 are connected to the three pad portions 160, respectively.The terminal portions 171 are connected to the pad portions 170,respectively. The terminal portion 181 is connected to the pad portion180.

In this embodiment, all of the terminal portions 111, 121, 141, 151,161, 171, 181, 191 are not equally spaced from each other. For instance,of the terminal portions 141, 151, 171, 181, which are aligned on oneside in the direction y, the terminal portions 141, 171, 181 arearranged at equal intervals in the direction x. As compared to this, theinterval between adjacent terminal portions 151 and the interval betweenthe terminal portions 151 and the terminal portion 171 adjacent to theterminal portions 151 are clearly large. The grooves 710 of the sealingresin 700, which are described later, and the arcuate cutouts of theisland portions 150 are located between the terminal portions 151 andbetween the terminal portion 171 and the terminal portions 151 arrangedat larger intervals.

The terminal portion 191 is provided at a distant position on one of thetwo ends spaced in the direction x. In this embodiment, the terminalportion 191 is not electrically connected to the island portions 110,120, 130, 140 or the semiconductor elements 410, 420, 430, 440.

Of the terminal portions 111, 121, 161 which are aligned on the otherside in the direction y, the three terminal portions 161 are arranged atrelatively small intervals. As compared to this, the interval betweenadjacent terminal portions 121 and the interval between the terminalportion 121 on each end and the adjacent terminal portion 111 or 161 areclearly large. The interval between the terminal portions 191 and theadjacent terminal portion 111 is larger than these intervals.

The intervals between the terminal portions 111, 121, 141, 151, 161,171, 181, 191 are set as described above in view of the function of eachterminal portion. For instance, when the semiconductor device A1 of thisembodiment is configured as an IPM, three-phase alternating currenthaving a U-phase, a V-phase and a W-phase is to be controlled by thesemiconductor device A1. The three terminal portions 121 are assigned asthe terminal portions for the U-phase, V-phase and W-phase,respectively. Moreover, to the three terminal portions 151, a relativelyhigh voltage is applied. These terminal portions, to which a relativelylarge current or voltage is applied, are arranged at relatively largeintervals, as described above.

The heat dissipation member 200 is provided mainly to dissipate heatfrom the semiconductor elements 410, 420 to the outside of thesemiconductor device A1. In this embodiment, the heat dissipation member200 is made of a ceramic material and in the form of a rectangularplate. Although a ceramic material is preferable as the material for theheat dissipation member of the present invention in terms of strength,thermal conductivity and insulating properties, other materials can beused if the use of such a material provides the effect the presentinvention aims for. Although it is preferable for the thicknessreduction of the semiconductor device A1 that the heat dissipationmember 200 is in the form of a plate, the heat dissipation member of thepresent invention may have other shapes.

The heat dissipation member 200 includes a bonding surface 210, anexposed surface 220 and a side surface 230. The bonding surface 210 andthe exposed surface 220 face away from each other in the thicknessdirection of the heat dissipation member 200 and are parallel to eachother. The bonding surface 210 is bonded to the island portion 110 andthe three island portions 120 via a bonding layer 300. In thisembodiment, as viewed in the direction z, the heat dissipation member200 overlaps not only the island portions 110, 120 but also at leastpart of the island portions 130, 140. However, the heat dissipationmember 200 is not bonded to the island portions 130, 140.

The bonding layer 300 bonds the heat dissipation member 200 and theisland portions 110, 120 to each other. Preferably, the bonding layer300 is configured to be able to properly bond the island portions 110,120 made of e.g. Cu to the heat dissipation member 200 made of a ceramicmaterial and have good thermal conductivity. For instance, an adhesivemade of a resin having good thermal conductivity is used as the bondinglayer 300.

FIG. 19 selectively illustrates the heat dissipation member 200, theisland portions 110, 120 and the bonding layer 300 for easierunderstanding. As illustrated in the figure, in this embodiment, thebonding layer 300 is made up of a plurality of individual regions 310.The individual regions 310 are separate from each other. The individualregions 310 are formed correspondingly to the island portion 110 and thethree island portions 120. Thus, the number of the individual regions310 is four. In this embodiment, as viewed in the direction z, each ofthe individual regions 310 is smaller than the corresponding one of theisland portions 110, 120, and the outer edge of each individual region310 is located inward of the outer edge of the corresponding islandportion 110, 120. With this arrangement of the bonding layer 300, thebonding surface 210 of the heat dissipation member 200 is exposedwithout being covered by the bonding layer 300 at portions betweenadjacent island portions 110, 120.

To bond the heat dissipation member 200 and the island portions 110, 120to each other with the bonding layer 300, an adhesive to become thebonding layer 300 is printed in a pattern on the heat dissipation member200. Then, with the island portions 110, 120 adhered to thepattern-printed adhesive, the adhesive is allowed to harden.

The exposed surface 220 is a surface exposed from the sealing resin 700.In use of the semiconductor device A1, the exposed surface 220 isbrought into contact with e.g. a heat dissipation plate (not shown). Inthis embodiment, the exposed surface 220 is flush with a surface of thesealing resin 700 which surrounds the exposed surface 220.

The side surface 230 of the heat dissipation member 200 connects thebonding surface 210 and the exposed surface 220 to each other andextends in the thickness direction. In this embodiment, as viewed in thedirection z, the side surface 230 is in the form of a rectangle made upof a plurality of lines. In other words, the side surface 230 extendsalong the entire periphery of the heat dissipation member 200. In thisembodiment, the entirety of the side surface 230 is covered by thesealing resin 700.

FIG. 11 is a sectional view illustrating a principal portion of thesection illustrated in FIG. 10 as enlarged. As shown in the figure, theside surface 230 of this embodiment includes a smooth portion 231 and arough portion 232. The smooth portion 231 is positioned closer to theexposed surface 220 and connected to the exposed surface 220. The roughportion 232 is farther away from the exposed surface 220 than the smoothportion 231 is. The smooth portion 231 is a surface smoother than therough portion 232. In other words, the rough portion 232 is a surfacerougher than the smooth portion 231. In this embodiment, the smoothportion 231 is a surface extending along the direction z. The roughportion 232 also extends generally along the direction z. As viewed inthe direction z, the rough portion 232 is positioned slightly inward ofthe smooth portion 231. In this embodiment, the boundary between thesmooth portion 231 and the rough portion 232 extends along the directionx or the direction y and is parallel to the exposed surface 220.

FIG. 12 illustrates a ceramic material plate 201 used for making theheat dissipation member 200. The ceramic material plate 201 is formedwith a groove 202. The groove 202 may be formed by laser processing.Alternatively, the groove 202 may be formed by forming a groove in arelatively soft ceramic material before hardening in the process ofmaking the ceramic material plate 201. By dividing the ceramic materialplate 201 along the groove 202, a plurality of heat dissipation members200 are obtained as shown in FIG. 13. The portion which has been thegroove 202 becomes the rough portion 232, and the broken surface formedby the division becomes the smooth portion 231.

FIG. 14 illustrates a variation of the side surface 230. In thisvariation, the rough portion 232 is entirely inclined with respect tothe direction x. Specifically, the rough portion 232 is inclined todeviate toward the left in the direction x in FIG. 14 (inward of theheat dissipation member 200) as proceeding upward in the direction z.The rough portion 232 of this type is formed when the ceramic materialplate 201 is divided by using a V-shaped groove 202, as shown in FIG.15. Generally, when laser processing is employed to make a groove, thegroove has a V-shape like the groove shown in FIG. 15.

The semiconductor element's 410, 420, 430, 440 are functional elementsto make the semiconductor device A1 function as an IPM. In thisembodiment, the semiconductor elements 410, 420 are power semiconductorelements. The “power semiconductor element” in the present inventionrefers to e.g. an element into or from which three-phase electriccurrent as the target of control by the IPM is inputted or outputted.Typical examples of the power semiconductor element include an IGBT(Insulated-Gate Bipolar Transistor), a MOSFET (Metal-Oxide-SemiconductorField-effect Transistor) and a FRD (Fast Recovery Diode). Of these powersemiconductor elements, the one which uses SiC as the base material maybe employed. In this embodiment, for instance, the semiconductorelements 410 are IGBTs, whereas the semiconductor elements 420 are FRDs.

As shown in FIGS. 8-10, 16 and 17, each of the semiconductor elements410 has a bottom surface 411, and includes a semiconductor main body,two upper-surface electrodes 412 and a bottom-surface electrode 413. Theupper-surface electrodes 412 are formed on the upper surface of thesemiconductor element 410 which faces upward in the direction z. The twoupper-surface electrodes 412 may be embedded in the semiconductor mainbody (see FIG. 9) so that the upper surface of the semiconductor element410 is entirely flat (i.e., has no difference in level). For instance,the upper-surface electrodes 412 are made of Au. Wires 600, 650 arebonded to the upper-surface electrodes 412. The bottom-surface electrode413 is formed to cover the entire lower surface of the semiconductorelement 410 (more precisely, the entire lower surface of thesemiconductor main body). For instance, the bottom-surface electrode 413is made of Au or Ag. The bottom surface 411 is bonded to the islandportions 110, 120 via the bonding material 510. In this embodiment, thebottom surface 411 is provided by the bottom-surface electrode 413.

Each of the semiconductor elements 420 has a bottom surface 421, andincludes a semiconductor main body, an upper-surface electrode 422 and abottom-surface electrode 423. The upper-surface electrode 422 is formedon the upper surface of ° the semiconductor element 420 which facesupward in the direction z. For instance, the upper-surface electrode 422is made of Au. The wire 650 is bonded to the upper-surface electrode422. The bottom-surface electrode 423 is formed to cover the entirelower surface of the semiconductor element 420 (more precisely, theentire lower surface of the semiconductor main body). For instance, thebottom-surface electrode 423 is made of Au or Ag. The bottom surface 421is bonded to the island portions 110, 120 via the bonding material 510.In this embodiment, the bottom surface 421 is provided by thebottom-surface electrode 423.

The bonding material 510 functions to bond the semiconductor elements410 and 420 to the island portions 110 and 120. In this embodiment,solder is used as the bonding material 510. The solder as the bondingmaterial 510 bonds the semiconductor elements 410 and 420 to the islandportions 110 and 120 by hardening from the molten state. In thisembodiment, since the bottom-surface electrodes 413, 423 of thesemiconductor elements 410, 420 are made of Au or Ag while the islandportions 110, 120 are made of Cu, the wettability of the bottom surfaces411, 421 of the semiconductor elements 410, 420 to the solder, or thebonding material 510 in the molten state is higher than the wettabilityof the island portions 110, 120 to the solder.

Since the wettability to the bonding material 510 which is solder is asdescribed above, in the process of mounting the semiconductor elements410 and 420, solder in the molten state (bonding material 510) tends toadhere more to the bottom surfaces 411, 421 of the semiconductorelements 410, 420 than to the island portions 110, 120. In thisembodiment, therefore, the contact area of the solder in the moltenstate (bonding material 510) with the bottom surfaces 411, 421 of thesemiconductor elements 410, 420 becomes larger than the contact area ofthe solder with the island portions 110, 120. As a result, as shown inFIGS. 9, 10 and 17, the bonding material 510 has a shape that becomeslarger as proceeding upward in the direction z. As viewed in thedirection z, the bonding material 510 is smaller than the semiconductorelement 410, 420, and the outer edge of the bonding material 510 ispositioned inward of the outer edge of the semiconductor element 410,420. Thus, the bonding material 510 is positioned inward of the trench113, 123.

To mount the semiconductor elements 410 and 420, solder paste which isto become the bonding material 510 is applied to the island portions 110and 120. In this process, the solder paste is applied to the region ofthe island portion 110, 120 which is surrounded by the trench 113, 123.Preferably, the solder paste is applied to be as distant from the trench113, 123 as possible.

The semiconductor elements 430, 440 are semiconductor devices configuredfor implementing required control with respect to the powersemiconductor elements. In the illustrated embodiment, each of thesemiconductor elements 430, 440 is a driver IC. More specifically, Thesemiconductor element 430 is a high-voltage driver IC for coping with arelatively high voltage current, whereas the semiconductor element 440is a low-voltage driver IC for coping with a relatively low voltagecurrent.

Referring to FIG. 3, the semiconductor elements 430, 440 haveupper-surface electrodes 432, 442 to which wires 600 are bonded at anend. As shown in FIG. 7, the semiconductor element 430 is bonded to theisland portion 130 via a bonding material 520. For instance, the bondingmaterial 520 is Ag paste. The semiconductor element 440 is also bondedto the island portions 140 via a bonding material 520 which is e.g. Agpaste.

The passive components 490 are electronic components having a singlefunction such as a resistor, a capacitor or a coil. In this embodiment,the passive components 490 act on the current flowing to thesemiconductor element 430. The passive components 490 are bonded to theisland portions 150 via a bonding material 520. Wires 600 are bonded tothe upper surfaces of the passive components 490 in the direction z.

The wires 600 and the wires 650 provide, along with the lead 100, anelectrical conduction path for allowing the semiconductor elements 410,420, 430, 440 and the passive components 490 to perform predeterminedfunctions. In this embodiment, the wires 600 provide an electricalconduction path for flowing a relatively small current, whereas thewires 650 provide an electrical conduction path for flowing a relativelylarge current. For instance, the wires 600 are made of Au and about 38μm in diameter. For instance, the wires 650 are made of Al and about 400μm in diameter.

FIG. 20 is a magnified photograph showing a part of the wire 600. FIGS.21-29 illustrate an example of a wire bonding process for forming thewire 600. As shown in FIG. 20, the wire 600 includes a second bondingportion 620, a stepped portion 605 and a reinforcing bonding portion630. As understood from FIG. 23, the wire 600 has a first bondingportion 610 as well.

FIGS. 21-29 illustrate a wire bonding process, taking the wire 600 forconnecting the upper-surface electrode 432 of the semiconductor element430 and the island portion 150 as an example. All the wires 600 of thisembodiment are formed by the same wire bonding process.

First, as shown in FIG. 21, a capillary Cp is prepared. The capillary Cphas a cylindrical shape with a through-hole and a gently curved end. Thecapillary Cp is capable of paying out a wire W made of Au which is thematerial for the wire 600. After the wire W is paid out from thecapillary Cp, a spark is applied to the end of the wire W, whereby aball Wb is formed.

Then, as shown in FIG. 22, the capillary Cp is moved down to press theball Wb against the upper-surface electrode 432 of the semiconductorelement 430. By this operation, the ball Wb is squashed by theupper-surface electrode 432 and the end of the capillary Cp. Thesquashed ball Wb becomes the first bonding portion 610, which is theportion bonded to the upper-surface electrode 432.

Then, as shown in FIG. 23, the capillary Cp is moved upward and thenmoved to a position directly above the island portion 150 while payingout the wire W. Then, the capillary Cp is moved downward, whereby theend of the capillary Cp is pressed against the island portion 150. Bythis operation, the wire W is sandwiched between the end of thecapillary Cp and the island portion 150 and cut. By this cutting, thewire 601 is provided which is bonded to the upper-surface electrode 432of the semiconductor element 430 and the island portion 150.

Of the wire 601, the portion bonded to the island portion 150 is thesecond bonding portion 620. The second bonding portion 620 is theportion of the wire W which is deformed by the end of the capillary Cp.The wire 601 has a stepped portion 605 at the boundary between theportion that has been in contact with the capillary Cp and the portionthat has not been in contact with the capillary Cp. The wire 601 iscircular in cross section at the portions closer to the first bondingportion 610 than the stepped portion 605 is. On the other hand, thesecond bonding portion 620, which is closer to the cut end of the wirethan the stepped portion 605 is, becomes smaller in thickness asproceeding toward the cut end.

Then, as shown in FIG. 25, with the paying out of the wire W stopped,the capillary Cp is moved upward. A trace 690 of the capillary CP isleft on the island portion 150 at the portion which the capillary Cp hasbeen pressed against and in direct contact with. The trace 690 has ashape corresponding to the shape of the end of the cylindrical capillaryCp and e.g. annular.

Then, as shown in FIG. 26, the capillary Cp is slightly moved to theleft in the figure. By this movement, the center axis (indicated by thesingle-dashed lines in the figure) of the capillary Cp is shifted towardthe second bonding portion 620. Then, as shown in FIG. 27, a ball Wb isformed at the end of the wire W.

Then, as shown in FIG. 28, the capillary Cp is moved downward. By thisoperation, the ball Wb is squashed by the island portion 150 and the endof the capillary Cp. The squashed ball Wb becomes a disk portion 631 anda columnar portion 632. The disk portion 631 is the portion sandwichedand spread between the end of the capillary Cp and the island portion150. The columnar portion 632 is the portion deformed along thethrough-hole of the capillary Cp at the end of the through-hole with alarge compressive force. The columnar portion 632 is smaller in diameterthan the disk portion 631.

Then, as shown in FIG. 29, the capillary Cp is moved upward, whereby thewire W is cut. In this way, a reinforcing bonding portion 630 isprovided which includes a peak portion 633 in addition to the diskportion 631 and the columnar portion 632. The peak portion 633 is theportion having a shape sticking upward as a result of the pulling andcutting of the wire W. In this way, the wire 600 is completed.

In this embodiment, as shown in FIGS. 20 and 29, the reinforcing bondingportion 630 overlaps at least a part of the second bonding portion 620and exposes the stepped portion 605. The reinforcing bonding portion 630exposes a portion of the trace 690 which is on the opposite side of thesecond bonding portion 620. Specifically, the reinforcing bondingportion 630 covers a half or more of the trace 690 on the opposite sideof the second bonding portion 620.

In this embodiment, the wires 600 other than the above-described wire600 are also appropriately formed with the reinforcing bonding portions630. The first bonding portions 610 of the wires 600 shown in FIG. 3 arebonded to the upper-surface electrode 432 of the semiconductor element430 or the upper-surface electrode 442 of the semiconductor element 440.The second bonding portions 620 of the wires 600 are bonded to theupper-surface electrodes 412 of the semiconductor elements 410, thepassive components 490, the island portions 150 and the pad portions170, 180.

The sealing resin 700 covers the lead 100, the semiconductor elements410, 420, 430, 440, the passive components 490 and the wires 600, 650partially or entirely. For instance, the sealing resin 700 is made of ablack epoxy resin.

As shown in FIG. 2, the sealing resin 700 is formed with four grooves710 and two grooves 720. The four grooves 710 are dented in thedirection y and elongated in the direction z. The grooves 710 areprovided between adjacent terminal portions 151, between a terminalportion 171 and the adjacent terminal portion 151, and at a positionadjacent one of the terminal portion 151. As shown in FIG. 3,correspondingly to these grooves 710, arcuate cutouts are formed in theisland portions 150. As noted above, the intervals between the threeterminal portions 151 are made relatively large.

The two grooves 720 are provided at the two ends spaced apart from eachother in the direction x. The two grooves 720 are dented in thedirection x and elongated in the direction z. For instance, the grooves720 may be utilized in transferring or mounting the semiconductor deviceA1.

As understood from FIGS. 6, 7, 9, 10 and 17, the recesses 112, 122, 132,142, 152, 182 and the trenches 113, 123 of the lead 100 are filled withthe sealing resin 700. In this embodiment, the sealing resin 700 coversthe entirety of the side surface 230 of the heat dissipation member 200.The surface of the sealing resin 700 which faces downward in thedirection z is flush with the exposed surface of the heat dissipationmember 200.

As shown in FIG. 18, the sealing resin 700 includes a subsequent portion730. The subsequent portion 730 is made of the same material as theother portions of the sealing resin 700, but made at a different timing(after the above-mentioned other portions are formed). Thus, thesubsequent portion 730 exists as a trace implying the manufacturingorder.

For instance, in the process of making the semiconductor device A1, thesealing resin is formed by using a die nearly at the end of the process.In this step, as to the island portion 120 shown in FIG. 16, the portionwhich is to become the terminal portion 121 supports the island portion120. Thus, the portion of the island portion 120 which is on theopposite side of the terminal portion 121 is not reliably supported andcan be unstable. Thus, before loading a resin material in a liquid stateinto the mold, a portion adjacent to the corner 125 of the islandportion 120 is pressed by a rod member. In this state, the resinmaterial is loaded and allowed to harden. After the resin is hardened toa certain degree, the rod member is removed, and resin material isquickly loaded into the space formed by removing the rod member. Theportion formed in this way by the later loading of the resin material isthe subsequent portion 730 shown in FIG. 18. Thus, the subsequentportion 730 is provided at a position closer to the corner 125 than tothe arcuate portion 126 of the island portion 120 and reaches theobverse surface of the sealing resin 700 and is in the form of a columnelongated in the direction z in this embodiment.

The advantages of the semiconductor device A1 are described below.

According to this embodiment, as shown in FIG. 19, the bonding layer 300includes a plurality of individual regions 310 that are separate fromeach other and provided for the respective island portions 110, 120. Thebonding surface 210 of the heat dissipation member 200 is exposedwithout being covered by the bonding layer 300 at portions betweenadjacent ones of the island portions 110, 120. As shown in FIG. 6, thesealing resin 700 is in contact with the exposed portions of the heatdissipation member 200. The heat dissipation member 200 made of e.g. aceramic material is bonded to the sealing resin 700 made of e.g. anepoxy resin with a relatively high bonding strength. Thus, detachment ofthe sealing resin 700 is prevented at the portions between the islandportions 110, 120. Thus, in selecting the material for the bonding layer300, the bonding strength of the material with the sealing resin 700does not need to be much considered. Thus, as the material for thebonding layer 300, a material that can properly bond the heatdissipation member 200 and the island portions 110, 120 and that hasgood thermal conductivity can be selected.

As shown in FIG. 19, the outer edges of the individual regions 310 arepositioned inward of the outer edges of the island portions 110, 120 asviewed in the direction z. This allows the heat dissipation member 200to be exposed as much as possible between the island portions 110, 120.This arrangement is suitable for the prevention of detachment of thesealing resin 700.

In this embodiment, four individual regions 310 are providedcorrespondingly to the single island portion 110 and the three islandportions 120. This arrangement allows the heat dissipation member 200 tobe exposed between each of the gaps between adjacent ones of the islandportions 110, 120. This arrangement is suitable for the prevention ofdetachment of the sealing resin 700.

The island portions 110, 120, on which the semiconductor elements 410,420 are mounted, have relatively large areas. According to thisembodiment, in spite of such large areas, the island portions 110, 120can be bonded reliably by selecting a suitable material for the bondinglayer 300 in view of the bonding strength and the thermal conductivity.

According to this embodiment, as shown in FIG. 11, the side surface 230of the heat dissipation member 200 has the smooth portion 231 and therough portion 232. Since the smooth portion 231 is relatively smooth,moisture may enter the boundary between the smooth portion 231 and thesealing resin 700 relatively easily. On the other hand, since the roughportion 232 is a relatively rough surface, the rough portion 232 and thesealing resin 700 are closely bonded to each other. Thus, even ifmoisture enters along the smooth portion 231, further ingress ofmoisture is prevented by the portion where the rough port ion 232 andthe sealing resin 700 are bonded to each other. Thus, separation of thesealing resin 700 and the heat dissipation member 200 is prevented.

Since the side surface 230 is formed along the entire edge of the heatdissipation member 200, ingress of moisture and so on is prevented alongthe entire edge of the heat dissipation member 200. Since the sidesurface 230 is entirely covered by the sealing resin 700, ingress ofmoisture and so on is more reliably prevented. Since the exposed surface220 is flush with the sealing resin 700, at the outer end of theboundary between the side surface 230 and the sealing resin 700, theheat dissipation member 200 and the sealing resin 700 are in closecontact with each other. This also contributes to prevention of moistureingress. Moreover, since the boundary between the smooth portion 231 andthe rough portion 232 is parallel to the exposed surface 220, ingress ofmoisture and so on is prevented uniformly at the side surface 230.

Moreover, in this embodiment, each wire 600 has the reinforcing bondingportion 630 overlapping the second bonding portion 620. The reinforcingbonding portion 630 does not cover the stepped portion 605 where thediameter of the wire 600 suddenly reduces. However, the reinforcingbonding portion 630 reliably covers the part of the second bondingportion 620 which has a small thickness. This arrangement enhances thebonding strength of the relatively thin second bonding portions 620 tothe island portions 150, the upper-surface electrodes 412 of thesemiconductor elements 410, the passive components 490 and the padportions 170, 180, and thereby prevents detachment of the wires 600.

As shown in FIG. 20, the reinforcing bonding portion 630 exposes a partof the trace 690. The trace 690 is the trace of the capillary Cp pressedin forming the second bonding portion 620. To provide the reinforcingbonding portion 630 at a position that exposes the trace 690 means thatthe reinforcing bonding portion 630 is prevented from being positionedunduly far away from the second bonding portion 620. This reliablyprevents detachment of the second bonding portion 620. The reinforcingbonding portion 630 covers a half or more of the trace 690, which meansthat the reinforcing bonding portion 630 covers a large portion of thesecond bonding portion 620. This is suitable for the prevention ofdetachment of the second bonding portion 620.

In this embodiment, as described with reference to FIGS. 9, 10 and 17,the bottom surfaces 411, 412 of the semiconductor elements 410, 420 havehigher wettability to the bonding material 510 in a molten state thanthe island portions 110, 120. Thus, the bonding material 510 in a moltenstate spreads across the bottom surfaces 411, 412 of the semiconductorelements 410, 420, while the contact surface with the island portions110, 120 is reduced. As a result, when the bonding material 510 ishardened, the contact portion of the bonding material 510 with theisland portions 110, 120 is relatively small, whereby the thickness ofthe bonding material 510 increases. Thus, even when thermal stress isapplied on the bonding portions of the semiconductor elements 410, 420and the island portions 110, 120, the thermal stress is absorbed by thebonding material 510, so that detachment of the semiconductor elements410, 420 is prevented.

The provision of the bottom-surface electrodes 413, 423 on thesemiconductor elements 410, 420 is suitable for enhancing thewettability of the bottom surfaces 411, 421 to the bonding material 510in a molten state. The thickness of the bonding material 510 isincreased by forming the bottom-surface electrodes 413, 423 on theentire lower surfaces of the semiconductor elements 410, 420. Thebottom-surface electrodes 413, 423 made of Au or Ag is suitable forenhancing the wettability to the bonding material 510 which is solder.

Since the island portions 110, 120 are formed with the trenches 113,123, the bonding material 510 in a molten state is prevented from undulyspreading. Even when the bonding material 510 in the molten state flowsto the trench 113, the bonding material 510 cannot spread beyond theedge of the trench 113 due to surface tension, whereby the moltenbonding material 510 is stopped. Since the trenches 113, 123 surroundthe entire semiconductor elements 410, 420, spreading of the bondingmaterial 510 is reliably prevented.

According to this embodiment, the recess 112, 122, 132, 142, 152, 182are provided at appropriate portions of the lead 100. Since the sealingresin 700 enters the recesses 112, 122, 132, 142, 152, 182, the bondingstrength of the sealing resin 700 to the lead 100 is enhanced. Thus,separation of the lead 100 from the sealing resin 700 is prevented.

The island portions 110, 120 are not formed with the recesses 112, 122at portions which overlap the semiconductor elements 410, 420, and theseportions are made flat. Thus, bonding of the semiconductor elements 410,420 by using the bonding material 510 is achieved properly. Moreover, inthe island portions 110, 120, a plurality of recesses 112, 122 arearranged so as to surround the semiconductor elements 410, 420. Withthis arrangement, the sealing resin 700 is strongly bonded to the islandportions 110, 120 around the semiconductor elements 410, 420. Thus,detachment of the sealing resin 700 is prevented, which also preventsgeneration of gaps leading to the semiconductor elements 410, 420 due todetachment of the sealing resin 700. Since such gaps are not formed,insulation of the semiconductor elements 410, 420 is properlymaintained.

As shown in FIG. 16, the island portion 120 is provided with the arcuateportion 126. Detachment of the sealing resin 700 from the lead 100 isunlikely to occur from the arcuate portion 126 having a gently curvedshape. Thus, provision of the arcuate portion 126 contributes toprevention of detachment of the sealing resin 700 from the lead 100. Onthe other hand, owing to the provision of the corners 125, the islandportion 120 secures a certain amount of area at a portion close to itsend. As described with reference to FIG. 18, this portion can be used tohold the island portion 120 in the process of forming the sealing resin700.

Since the corners 125 are spaced farther away from the terminal portion121 than the semiconductor elements 410, 420 are, the island portion 120can be held stably. The fact that the arcuate portion 126 is closer tothe terminal portion 121 than the semiconductor elements 410, 420 aremeans that the arcuate portion 126 is closer to the outer surface of thesealing resin 700 than the semiconductor elements 410, 420 are.Generally, the effect of e.g. thermal stress is larger at portionscloser to the outer surface of the sealing resin 700. Since the arcuateportion 126 is provided at such a portion where detachment is morelikely to occur, detachment of the sealing resin 700 is effectivelyprevented.

FIG. 30 shows a semiconductor device according to a second embodiment ofthe present invention. In this figure, the elements that are identicalor similar to those of the foregoing embodiment are designated by thesame reference signs as those used for the first embodiment.

The semiconductor device A2 of this embodiment differs from theabove-described embodiment in structure of the island portions 110, 120.In this embodiment, the island portion 110 includes corners 115 andarcuate portions 116. Moreover, each of the island portions 120 hascorners 125 and an arcuate portion 126.

The corners 115 are provided at the upper end in the figure (i.e. on theside farther away from the terminal portion 111). The arcuate portion116 is provided on the lower end in the figure (i.e. on the side closerto the terminal portion 111). The corners 115 are on the upper side ofthe semiconductor elements 410, 420 in the figure (on the side fartheraway from the terminal portion 111), whereas the arcuate portion 116 ison the lower side of the semiconductor elements 410, 420 i.e. on theside closer to the terminal portion 111). At each of the corners 115,two sides of the island portion 120 are connected to each other to forman angle of 90°. At each arcuate portion 116, two sides of the islandportion 120 are connected to each other to form an arc.

According to this embodiment, in the process of forming the sealingresin 700, all the island portions 110, 120 are reliably fixed so thatdetachment of the sealing resin 700 is reliably prevented.

The semiconductor device according to the present invention is notlimited to the foregoing embodiments. The specific structure of eachpart of the semiconductor device according to the present invention maybe varied in design in many ways.

The structures of the present invention and the variations are describedbelow as appendixes.

APPENDIX 1A

A semiconductor device comprising:

a semiconductor element;

a lead including an island portion on which the semiconductor element ismounted;

a heat dissipation member for dissipating heat from the island portion;and

a sealing resin covering the semiconductor element, the island portionand a part of the heat dissipation member, wherein:

the heat dissipation member is made of a ceramic material and includesan exposed surface exposed from the sealing resin and a side surfaceconnected to the exposed surface and at least partially covered by thesealing resin, and

the side surface includes a smooth port ion that is relatively smoothand positioned closer to the exposed surface and a rough portion that isrelatively rough and positioned farther away from the exposed surfacethan the smooth portion is.

APPENDIX 2A

The semiconductor device according to Appendix 1A, wherein the sidesurface is provided along an entire periphery of the heat dissipationmember.

APPENDIX 3A

The semiconductor device according to Appendix 1A or 2A, wherein theside surface is entirely covered by the sealing resin.

APPENDIX 4A

The semiconductor device according to any one of Appendixes 1A-3A,wherein the exposed surface is flush with the sealing resin.

APPENDIX 5A

The semiconductor device according to any one of Appendixes 1A-4A,wherein the rough portion is positioned inward of the smooth portion asviewed in plan.

APPENDIX 6A

The semiconductor device according to any one of Appendixes 1A-5A,wherein the smooth portion is perpendicular to the exposed surface.

APPENDIX 7A

The semiconductor device according to any one of Appendixes 1A-6A,wherein the rough portion is inclined so as to be shifted inward asviewed in plan as proceeding farther away from the exposed surface.

APPENDIX 8A

The semiconductor device according to any one of Appendixes 1A-7A,wherein the side surface comprises a plurality of portions which arelinear as viewed in plan.

APPENDIX 9A

The semiconductor device according to Appendix 8A, wherein the heatdissipation member is rectangular.

APPENDIX 10A

The semiconductor device according to any one of Appendixes 1A-9A,wherein a boundary between the smooth portion and the rough portion isparallel to the exposed surface.

APPENDIX 11A

The semiconductor device according to any one of Appendixes 1A-10A,wherein

two semiconductor elements are provided,

the lead includes two island portions on which the semiconductorelements are mounted, respectively,

the semiconductor device further comprises a bonding layer that bondsthe two island portions and the heat dissipation member to each other,

the bonding layer includes two individual regions provided for therespective island portions and separate from each other.

APPENDIX 12A

The semiconductor device according to Appendix 11A, wherein each of theindividual regions has an outer edge positioned inward of an outer edgeof a corresponding one of the island portions as viewed in plan.

APPENDIX 13A

The semiconductor device according to Appendix 11A or 12A, wherein theheat dissipation member is in a form of a plate.

APPENDIX 14A

The semiconductor device according to any one of Appendixes 11A-13A,wherein the semiconductor element is a power semiconductor element.

APPENDIX 15A

The semiconductor device according to any one of Appendixes 11A-14A,wherein:

a plurality of the semiconductor elements are provided;

the lead includes a plurality of the island portions; and

the bonding layer includes the same number of the individual regions asthe island portions.

APPENDIX 16A

The semiconductor device according to Appendix 15A, wherein two or moreof the semiconductor elements are mounted on at least one of theplurality of island portions.

APPENDIX 17A

The semiconductor device according to Appendix 15A or 16A, wherein theplurality of island portions are aligned in one direction.

APPENDIX 18A

The semiconductor device according to any one of Appendixes 15A-17A,wherein the lead includes a plurality of terminal portions connected tothe island portions, respectively, and exposed from the sealing resin.

APPENDIX 19A

The semiconductor device according to any one of Appendixes 11A-18A,wherein each of the island portions is formed with a plurality ofrecesses.

APPENDIX 20A

The semiconductor device according to any one of Appendix 19A, whereinthe recesses are arranged so as to surround the semiconductor element.

APPENDIX 1B

A semiconductor device comprising:

a semiconductor element;

a lead on which the semiconductor element is mounted; and

a wire bonded to the semiconductor element,

wherein the wire includes a first bonding portion, a second bondingportion that gradually reduces in thickness from a boundary provided bya stepped portion, and a reinforcing bonding portion that overlaps atleast apart of the second bonding portion and exposes the steppedportion.

APPENDIX 2B

The semiconductor device according to Appendix 1B, wherein thereinforcing bonding portion includes a disk portion that is in contactwith the second bonding portion.

APPENDIX 3B

The semiconductor device according to Appendix 2B, wherein thereinforcing bonding portion includes a columnar portion that is formedon the disk portion, smaller in diameter than the disk portion andconcentric with the disk portion.

APPENDIX 4B

The semiconductor device according to Appendix 3B, wherein thereinforcing bonding portion includes a peak portion formed on thecolumnar portion.

APPENDIX 5B

The semiconductor device according to any one of Appendixes 1B-4B,wherein a portion at which the second bonding portion is bonded isformed with a trace generated by pressing a capillary in forming thesecond bonding portion.

APPENDIX 6B

The semiconductor device according to Appendix 5B, wherein thereinforcing bonding portion exposes a part of the trace.

APPENDIX 7B

The semiconductor device according to Appendix 6B, wherein thereinforcing bonding portion covers a half or more of the trace which ison a side closer to the second bonding portion.

APPENDIX 8B

The semiconductor device according to any one of Appendixes 1B-7B,wherein the first bonding portion is bonded to the semiconductorelement.

APPENDIX 9B

The semiconductor device according to Appendix 8B, wherein the secondbonding portion is bonded to an additional semiconductor element.

APPENDIX 10B

The semiconductor device according to Appendix 8B, wherein the secondbonding portion is bonded to the lead.

APPENDIX 11B

The semiconductor device according to any one of Appendixes 1B-10B,wherein the wire is made of Au.

APPENDIX 12B

The semiconductor device according to any one of Appendixes 1B-11B,wherein:

the lead includes an island portion on which the semiconductor elementis mounted,

the semiconductor device further comprises a sealing resin covering thesemiconductor element and the island portion, and

the island portion is formed with a plurality of recesses.

APPENDIX 13B

The semiconductor device according to Appendix 12B, wherein the islandportion has a smooth surface at a portion that overlaps thesemiconductor element.

APPENDIX 14B

The semiconductor device according to Appendix 12B or 13B, wherein eachof the recesses is circular in cross section.

APPENDIX 15B

The semiconductor device according to one of Appendixes 12B-14B, whereinthe recesses are arranged so as to surround the semiconductor element.

APPENDIX 16B

The semiconductor device according to any one of Appendixes 12B-15B,wherein the recesses are arranged in a matrix.

APPENDIX 17B

The semiconductor device according to Appendix 16B, wherein the recessare arranged at equal intervals.

APPENDIX 18B

The semiconductor device according to any one of Appendixes 12B-17B,wherein the lead includes a pad portion on which the semiconductorelement is not mounted and a wire is connected, and

the pad portion is formed with a plurality of recesses.

APPENDIX 19B

The semiconductor device according to any one of Appendixes 12B-18B,wherein:

each of the semiconductor elements has a bottom surface,

the semiconductor device further comprises a bonding material that bondsthe bottom surface and the island portion to each other after being in amolten state, and

the bottom surface of the semiconductor element has a higher wettabilityto the bonding material in a molten state than that of the islandportion.

APPENDIX 20B

The semiconductor device according to Appendix 19B, wherein the islandportion includes a trench positioned on an outer side of thesemiconductor element.

APPENDIX 21B

The semiconductor device according to Appendix 20B, wherein the bondingmaterial is positioned inward of the trench.

APPENDIX 1C

A semiconductor device comprising:

a semiconductor element including a bottom surface;

a lead including an island portion on which the semiconductor element ismounted; and

a bonding material that bonds the bottom surface and the island portionto each other after being in a molten state,

the bottom surface of the semiconductor element has a higher wettabilityto the bonding material in a molten state than that of the islandportion.

APPENDIX 2C

The semiconductor device according to Appendix 1C, wherein thesemiconductor element includes a bottom-surface electrode that providesthe bottom surface.

APPENDIX 3C

The semiconductor device according to Appendix 2C, wherein thebottom-surface electrode is formed on an entire surface of thesemiconductor element on the bottom surface side.

APPENDIX 4C

The semiconductor device according to Appendix 2C or 3C, wherein thebonding material is electrically conductive.

APPENDIX 5C

The semiconductor device according to Appendix 4C, wherein the bondingmaterial is solder.

APPENDIX 6C

The semiconductor device according to Appendix 5C, wherein thebottom-surface electrode is made of Au or Ag.

APPENDIX 7C

The semiconductor device according to Appendix 6C, wherein the islandportions is made of Cu.

APPENDIX 8C

The semiconductor device according to any one of Appendixes 1C-7C,wherein the island portion includes a trench positioned on an outer sideof the semiconductor element.

APPENDIX 9C

The semiconductor device according to Appendix 8C, wherein the bondingmaterial is positioned inward of the trench.

APPENDIX 10C

The semiconductor device according to Appendix 9C, wherein the trenchsurrounds an entire periphery of the semiconductor element.

APPENDIX 11C

The semiconductor device according to any one of Appendixes 1C-10C,further comprising a sealing resin covering the semiconductor elementand the island portion,

wherein the island portion is formed with a plurality of recesses.

APPENDIX 12C

The semiconductor device according to Appendix 11C, wherein the islandportion has a smooth surface at a portion that overlaps thesemiconductor element.

APPENDIX 13C

The semiconductor device according to Appendix 11C or 12C, wherein eachof the recesses is circular in cross section.

APPENDIX 14C

The semiconductor device according to one of Appendixes 11C-13C, whereinthe recesses are arranged so as to surround the semiconductor element.

APPENDIX 15C

The semiconductor device according to any one of Appendixes 11C-14C,wherein the recesses are arranged in a matrix.

APPENDIX 16C

The semiconductor device according to Appendix 15C, wherein the recessare arranged at equal intervals.

APPENDIX 17C

The semiconductor device according to any one of Appendixes 11C-16C,wherein the lead includes a pad portion on which the semiconductorelement is mounted and a wire is connected, and the pad portion isformed with a plurality of recesses.

APPENDIX 18C

The semiconductor device according to any one of Appendixes 11C-17C,wherein the lead includes a terminal portion connected to the islandportion and exposed from the sealing resin, and

the island portion includes a corner where two discontinuous sides areconnected to each other and an arcuate portion that is positioned closerto the terminal portion than the corner is.

APPENDIX 19C

The semiconductor device according to Appendix 18C, wherein the corneris farther away from the terminal portion than the semiconductor elementis, and

the arcuate portion is closer to the terminal portion than thesemiconductor element is.

APPENDIX 20C

The semiconductor device according to Appendix 18C or 19C, wherein thesealing resin includes a subsequent portion which is provided at aposition closer to the corner than to the arcuate portion of the islandportion and which reaches an obverse surface of the sealing resin.

APPENDIX 1D

A semiconductor device comprising:

a semiconductor element;

a lead including an island portion on which the semiconductor element ismounted; and

a sealing resin covering the semiconductor element and the islandportion,

wherein the island portion is formed with a plurality of recesses.

APPENDIX 2D

The semiconductor device according to Appendix 1D, wherein the islandportion has a smooth surface at a portion that overlaps thesemiconductor element.

APPENDIX 3D

The semiconductor device according to Appendix 1D or 2D, wherein each ofthe recesses is circular in cross section.

APPENDIX 4D

The semiconductor device according to any one of Appendixes 1D-3D,wherein the recesses are arranged so as to surround the semiconductorelement.

APPENDIX 5D

The semiconductor device according to any one of Appendixes 1D-4D,wherein the recesses are arranged in a matrix.

APPENDIX 6D

The semiconductor device according to Appendix 5D, wherein the recessare arranged at equal intervals.

APPENDIX 7D

The semiconductor device according to any one of Appendixes 1D-6D,wherein the lead includes a pad portion on which the semiconductorelement is not mounted and a wire is connected, and

the pad portion is formed with a plurality of recesses.

APPENDIX 8D

The semiconductor device according to any one of Appendixes 1D-7D,wherein the lead includes a terminal portion connected to the islandportion and exposed from the sealing resin, and

the island portion includes a corner where two discontinuous sides areconnected to each other and an arcuate portion that is positioned closerto the terminal portion than the corner is.

APPENDIX 9D

The semiconductor device according to Appendix 8D, wherein the corner isfarther away from the terminal portion than the semiconductor elementis, and

the arcuate portion is closer to the terminal portion than thesemiconductor element is.

APPENDIX 10D

The semiconductor device according to Appendix 8D or 9D, wherein thesealing resin includes a subsequent portion which is provided at aposition closer to the corner than to the arcuate portion of the islandportion and which reaches an obverse surface of the sealing resin.

APPENDIX 11D

The semiconductor device according to any one of Appendixes 1D-10D,wherein:

the semiconductor element has a bottom surface,

the semiconductor device further comprises a bonding material that bondsthe bottom surface and the island portion to each other after being in amolten state, and

the bottom surface of the semiconductor element has a higher wettabilityto the bonding material in a molten state than that of the islandportion.

APPENDIX 12D

The semiconductor device according to Appendix 11D, wherein thesemiconductor element includes a bottom-surface electrode that providesthe bottom surface.

APPENDIX 13D

The semiconductor device according to Appendix 12D, wherein thebottom-surface electrode is formed on an entire surface of thesemiconductor element on the bottom surface side.

APPENDIX 14D

The semiconductor device according to Appendix 12D or 13D, wherein thebonding material is electrically conductive.

APPENDIX 15D

The semiconductor device according to Appendix 14D, wherein the bondingmaterial is solder.

APPENDIX 16D

The semiconductor device according to Appendix 15D, wherein thebottom-surface electrode is made of Au or Ag.

APPENDIX 17D

The semiconductor device according to Appendix 16D, wherein the islandportions is made of Cu.

APPENDIX 18D

The semiconductor device according to any one of Appendixes 11D-17D,wherein the island portion includes a trench positioned on an outer sideof the semiconductor element.

APPENDIX 19D

The semiconductor device according to Appendix 18D, wherein the bondingmaterial is positioned inward of the trench.

APPENDIX 20D

The semiconductor device according to Appendix 19D, wherein the trenchsurrounds an entire periphery of the semiconductor element.

1-20. (canceled)
 21. A semiconductor device comprising: a firstsemiconductor element; a lead including a first island portion on whichthe semiconductor element is mounted; a heat dissipation member made ofa ceramic material for dissipating heat from the island portion; and asealing resin covering the semiconductor element, the island portion anda part of the heat dissipation member, wherein the heat dissipationmember includes an exposed surface and a side surface connected to theexposed surface, the exposed surface being exposed from the sealingresin and the side surface being at least partially covered by thesealing resin, and the side surface includes a smooth portion and arough portion positioned farther away from the exposed surface than thesmooth portion is, the smooth portion being smoother than the roughportion.
 22. The semiconductor device according to claim 21, wherein theside surface is provided along an entire periphery of the heatdissipation member.
 23. The semiconductor device according to claim 21,wherein an entirety of the side surface is covered by the sealing resin.24. The semiconductor device according to claim 21, wherein the exposedsurface is flush with a surface of the sealing resin.
 25. Thesemiconductor device according to claim 21, wherein the rough portion ispositioned inward of the smooth portion as viewed in plan.
 26. Thesemiconductor device according to claim 21, wherein the smooth portionis perpendicular to the exposed surface.
 27. The semiconductor deviceaccording to claim 21, wherein the rough portion is inclined so as toshift inward as viewed in plan with increasing distance from the exposedsurface.
 28. The semiconductor device according to claim 21, wherein theside surface comprises a plurality of linear portions as viewed in plan.29. The semiconductor device according to claim 28, wherein the heatdissipation member is rectangular.
 30. The semiconductor deviceaccording to claim 21, wherein a boundary between the smooth portion andthe rough portion is parallel to the exposed surface.
 31. Thesemiconductor device according to claim 21, further comprising a secondsemiconductor element and a bonding layer, wherein the lead includes asecond island portion on which the second semiconductor element ismounted, the bonding layer bonds the first and the second islandportions to the heat dissipation member, and the bonding layer includesa first and a second individual regions provided for the first and thesecond island portions, respectively, the first individual region andthe second individual region being spaced apart from each other.
 32. Thesemiconductor device according to claim 31, wherein the first individualregion has an outer edge positioned inward of an outer edge of the firstisland portion as viewed in plan, and the second individual region hasan outer edge positioned inward of an outer edge of the second islandportion as viewed in plan.
 33. The semiconductor device according toclaim 31, wherein the heat dissipation member is in a form of a plate.34. The semiconductor device according to claim 31, wherein each of thefirst and the second semiconductor elements is a power semiconductorelement.
 35. The semiconductor device according to claim 21, furthercomprising a bonding layer and a plurality of semiconductor elementsincluding the first semiconductor element, wherein the lead comprises aplurality of island portions including the first island portion, thebonding layer bonds the plurality of island portions to the heatdissipation member, and the bonding layer includes a plurality ofindividual regions equal in number to the plurality of island portions.36. The semiconductor device according to claim 35, wherein at least twoof the plurality of semiconductor elements are mounted on one of theplurality of island portions.
 37. The semiconductor device according toclaim 35, wherein the plurality of island portions are aligned along acommon direction.
 38. The semiconductor device according to claim 35,wherein the lead includes a plurality of terminal portions that areconnected to the plurality of island portions and exposed from thesealing resin.
 39. The semiconductor device according to claim 21,wherein the island portion is formed with a plurality of recesses. 40.The semiconductor device according to claim 39, wherein the plurality ofrecesses are arranged to surround the semiconductor element.